Scoop dredge



June16, 1942. r, SMITH I 2,255,391

Filed Dec. 17, 1940 INVENTOR THOMAS 5MP? WML.

A'ITORNEY.

Patented June 16, 1942 Thomas Smith, Franklin, South Australia,

Australia.

Application December 17, 1940; Serial No; 370,456 In Australia September 10, 1939 4 Claims.

My invention relates to improvements in and connected with scoop dredges of that class which are adapted to work in conjunction with the customary type of ships winches for the unloading of loosematerial such as coal, rocksulphur, wheat and similar bulk cargo and is fitted with mechanism whereby a-locking weight which is used for controlling the opening or closing of the dredge is automatically released or alternatively brought into action.-

The elevation and position of the scoop or dredge is controlled by two chains,- cables or ropes which are operated by the ships winches namely, a main chain or wire cable which is attached to the midships winch, the arm of which is placed directly over the ships hold which contains the cargo to be unloaded, and a second chain or wire cable attached to the ship's yard arm winch which is placed at a suitable angle to determine the position for unloading the cargo. A transverse bar which is attached to the yoke is so disposed that it automatically ,makes contact with and influences locking mechanism which releases or fastens a weight to which awire cable is attached, the cable being extended to a transverse frame upon which the body of the dredge is supported.

The scoops of th dredge are constructed and suspended in such manner that together with supporting links the sides of' the dredge which are attached to the links constitute a direct acting lazy tongs device thereby making it possible for the dredge to perform its several functions with less purchases than are at present in general use for the purposes indicated.

But in order that my invention may b more clearly understood, I will now describe the same by aid of the accompanying illustrative drawing wherein:

Fig. 1 is a side elevation of the dredge when closed as in Fig. 2 and illustrates a transverse bar attached to the supporting yoke, the control weight being elevated.

Fig. 2 is an end view of the dredge in closed position as in Fig. 1 showing a weight and lever onone side of a central block and projecting arms on toothed segment wheels on the opposite side of the block.

Fig. 3 is an end view of the dredge extended to an open position.

Fig. 4 is a plan of the upper transverse frame wherein a downwardly directed control weight is contained and a yoke having a transverse bar which is in contact with outwardly extended bolts associated'with locking pawls and toothed segments. I

Fig. 5 is a sectional side elevation on larger scale showing the control weight resting onthe bottom ofthe block andindicating internal control mechanism.

In each of the illustrations similar letters of reference are used to denote similar or corresponding parts.

In the drawing and referring more particularly to the enlarged Fig. 5, a is the lower part of a control block having a separable covering plate a which is attached to the lower portion by the bolts a2. The control block a is provided with a vertical opening (13 which is reduced in size at the lower end as indicated at a4. Within this structure I supporta heavy weight b to the upper end of which achain or a strong wire cable is attached as indicated at b and leads to a winch, and to the bottom of the weight I fasten a strong wire-cable or chain b2 for attachment to thebody of a dredge as hereinafter described.

Intermediate of the upper and lower portions of the weight a cavity is formed-on opposite sides of the opening d through which horizontal rods 0 are accommodated each rod being supported in a correspondingly placed horizontal groove between the upper and lower portions of the block. Upon these rods and within the cavity area I fasten pawls d which are adapted to operate within the area of the cavity. These pawls are characterised by a horizontal base which is so constructed and situated that the pawls are capable of moving approximately one quarter of a revolution within the cavity and as more clearly illustrated in Fig. 5, their inner ends protrude into the upper portion of the cavity, their lower edges being horizontal and adapted to rest on the floor of the cavity at a slightly lower level than the upper portion of the top of the lower member of the block.. These elements are rendered automatic in their action in the following manner.

At one ndfof each of the horizontal rods upon which the-pawl is mounted, I fasten or extend lever arms e which are furnished with weights 6 whereby the pawls may be elevated to a horizontal position whereupon their ends protrude into the weight chamber but the pawls may be moved by the levers into a vertical or almost vertical position so as to leave a passage in the upper part of the interior of the block clear of the weight b.

On the opposite end of each of the horizontal rods external of the casting I fasten a segment f of a toothed wheel, the toothed segment being mor clearly illustrated in Fig. 1 of the drawing and upon each segment I fasten a protruding arm f.

This structure is mounted on a transverse frame 9 of the nature indicated in Fig. 4 and supported on a swinging yoke upon and above ,the frame 9, there being end members 9' through which the main hinge pins h protrude outwardly and support the outer downwardly directed arms 7' the lower ends of which ar hinged at 7" directly to the scoop or dredge k or to an extension thereof, the lower contacting edges of which are indicated at k, and which in the Figure 3 are substantially in horizontal alignment with the floor or the deck of a vessel or other place wherein or whereon the dredge is to be .used. These extensions 7c rotate upon the lower hinge pins 1' of the lower transverse frame I which is somewhat similar to the upper frame g the end structure is being reinforced if so desired by th plates k2 which may be slightly bevelled along their outer edges to facilitate the downward passage of the structure when operating on such material as wheat in bulk or upon ordinary soil which is to be elevated.

Referring now to Fig. 1 it will be seen that a connecting chain or wire cable b2 which is attached to the bottom of the weight b extends downwardly from the bottom of the weight I) through the centre of the block and around the sheave m which is mounted on the lower cross bar frame Z, upwardly to and around a sheave m on the upper cross bar or frame g and thence downwardly to the attachment n on the lower bar Z. An upward strain when imparted by an associated winch to the cable 2) and b2 results in drawing the inner hinged part of the dredge upwards from the position shown in Fig. 3 to the position shown in Fig. 2.

The yoke 0 which is suspended by the chain is hingedly attached to the ends of the framed member 9 by the bolts h and is characterised by a cross bar 0 which is so situated that when the dredge comes to rest on the ground or the dump the chain p is slackened, whereupon the yoke swings forward on its hinges h whereupon the cross bar 0' falls on to the protruding arms f of the toothed segments 1 thus forcing them downwards and simultaneously rotating the segment thereby bringing the pawls d to a vertical position and deflecting their ends clear of the passage in the weight block. This movement which clears the weight passage allows the main weight to ascend and as the weight ascends under the influence of a winding winch the lower transverse frame bar Z and the inner central part of the attached dredge structure is drawn upwards ultimately bringing the extended body segments k, k, together and subsequently the weights e on the levers e which latter are rotatably mounted within the block exert their influence and return the pawls d to a horizontal position so that by means of the associated winch the weight is drawn upwardly from the block and in so moving simultaneously causes that part of the wire cable which is attached to the bottom of the weight and which passes through the sheaves and is attached to the lower transverse bar to close the dredge by upward movement while the chain 10 which is attached to the yoke which supports the dredge is correspondingly swung to the desired position for carrying the load to its destination whereupon the strain on the rope b which supports the weight b is released so that the weight again descends into the central block and simultaneously allows the dredge to swing open and discharge its cargo on to a dump provided for that purpose, these elements being adapted to be used either for loading or for unloading the cargo according to requirements.

Having now fully described and ascertained my said invention and the manner in which it is to be performed, I declare that what I claim is:

l. A control device for a scoop bucket having upper and lower horizontal frames, bucket sections pivoted to the lower frame and lazy tong arms pivoted to the upper frame and bucket sections, respectively, said device comprising a control weight, a control block secured to said upper frame and being provided with a vertical passage for said weight and with a seat limiting the downward movement of said weight, a cable attached to the lower end of said weight and extending through an axial opening in said seat, said cable being arranged to pull the lower frame towards the upper frame and to close the bucket when said weight is lifted out of said control block, a control cable attached to the top of said weight, pivoted pawls mounted in said control block and being capable of assuming upper operative end positions, in which they project into said passage thereby permitting downward movement of the weight onto said seat but preventing upward movement of the weight from said seat, and a lower inoperative position in which said weight may travel freely through said passage, means holding said pawls normally in their operative upper positions, and means to connect a lifting cable with said upper frame, said connecting means including an element to move said pawls to their inoperative lower positions when the tension on the lifting cable is relieved.

2. A control device, as claimed in claim 1, comprising transverse shafts on which said pawls are fixed, each of said shafts carrying on one end thereof a crank pin, and said means to connect the upper frame with the lifting cable comprising a yoke swingably attached to the upper frame and including a bracket arranged for cooperation with said crank pins to turn said shafts and pawls to their inoperative positions when the yoke falls down as the tension on the lifting cable is relieved.

3. A control device, as claimed in claim 1, comprising transverse shafts on which said pawls are fixed, said means holding said pawls normally in their operative positions comprising crank arms on said shafts and weights on said crank arms.

4. A control device, as claimed in claim 1, comprising transverse shafts on which said pawls are fixed, one end of each shaft carrying a toothed segment, said toothed segments being in mesh with each other.

THOMAS SMITH. 

